Oil supply device

ABSTRACT

An oil supply device includes: an oil pump; an oil supply flow passage through which oil discharged from the oil pump flows; and an air mixing portion that cools a cooling object by mixing air into the oil supplied to the oil supply flow passage and supplying the oil mixed with the air to the cooling object.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2018-133292, filed on Jul. 13, 2018, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to an oil supply device, and more particularly to an oil supply device provided with an oil pump.

BACKGROUND DISCUSSION

In the related art, an oil supply device provided with an oil pump is known (for example, refer to JP 2017-218912A (Reference 1)).

The Reference 1 discloses a piston cooling device including an oil pump and a first oil jet and a second oil jet for injecting oil supplied from the oil pump to a piston to cool the piston. The first oil jet is configured to inject the oil toward an inlet/outlet hole of a cooling cavity provided on the inside of the piston and cool the piston by flowing the oil into the cooling cavity. The second oil jet is configured to cool the piston by injecting the oil toward a back surface of the piston.

In the piston cooling device described in Reference 1, the piston is cooled using at least one of the first oil jet and the second oil jet in accordance with the state of an engine. Here, in the piston cooling device, the piston is cooled by the oil having a heat transfer coefficient lower than that of a coolant. Therefore, in a case of a state (for example, the engine is in a high load state) of the engine in which the temperature of the piston is high, the oil is supplied to the piston from both the first oil jet and the second oil jet to prevent insufficient cooling compared to a case of cooling the piston by the coolant.

Therefore, in the piston cooling device described in Reference 1, it is necessary to hold the amount of oil that can be supplied to the piston from both the first oil jet and the second oil jet. As a result, there is a problem that the size of the device increases.

Thus, a need exists for an oil supply device which is not susceptible to the drawback mentioned above.

SUMMARY

An oil supply device according to an aspect of this disclosure includes: an oil pump; an oil supply flow passage through which oil discharged from the oil pump flows; and an air mixing portion that cools a cooling object by mixing air into the oil supplied to the oil supply flow passage and supplying the oil mixed with the air to the cooling object.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:

FIG. 1 is a schematic view schematically illustrating an entire configuration of an engine according to an embodiment;

FIG. 2 is a sectional view schematically illustrating the engine according to the embodiment;

FIG. 3 is a schematic view illustrating an oil pump according to the embodiment;

FIG. 4 is a schematic view illustrating an air mixing portion of an oil supply device according to the embodiment;

FIG. 5 is a schematic view of the air mixing portion of the oil supply device according to the embodiment when viewed from an oil discharge direction;

FIG. 6 is a schematic view illustrating a state where oil mixed with air is supplied to a cooling object by the oil supply device according to the embodiment;

FIG. 7 is a schematic view illustrating a state where the oil mixed with the air supplied by the oil supply device according to the embodiment is spread on a surface of the cooling object;

FIG. 8A is a schematic view illustrating a state where the oil mixed with the air is spread.

FIG. 8B is a schematic view illustrating a state where the oil that is not mixed with the air is spread.

FIG. 9 is a graph illustrating a relationship between a flow velocity and a heat transfer coefficient in each case where water, the oil mixed with the air, and the oil are supplied to the cooling object;

FIG. 10 is a sectional view schematically illustrating an engine according to a first modification example of the embodiment;

FIG. 11 is a schematic view illustrating an air mixing portion according to a second modification example of the embodiment;

FIG. 12 is a sectional view schematically illustrating an engine according to a third modification example of the embodiment;

FIG. 13 is a sectional view schematically illustrating an engine according to a fourth modification example of the embodiment;

FIG. 14 is a sectional view schematically illustrating an engine according to a fifth modification example of the embodiment; and

FIG. 15 is a schematic view illustrating an engine for supplying the oil mixed with the air supplied from an oil supply device according to a sixth modification example of the embodiment to a vehicle driving motor.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the disclosure will be described based on the drawings.

Schematic Configuration of Engine

As illustrated in FIG. 1, an engine 1 for a vehicle (automobile) is configured to continuously repeat one cycle of suction, compression, expansion (combustion), and exhaust, and rotate a crankshaft 10 as a piston 8 reciprocates respectively in a plurality (four) of cylinders 3 a that extend in an up-down direction. Here, in the engine 1, a direction in which the crankshaft 10 extends is referred to as an X direction, and a direction orthogonal to the X direction in a horizontal direction is referred to as a Y direction. Further, in the engine 1, a direction orthogonal to the X direction and the Y direction is referred to as a Z direction (up-down direction).

The engine 1 includes an engine main body 2 including a cylinder block 3, a cylinder head 4 fixed to a Z1 side of the cylinder block 3, and a crank case 5 fixed to a Z2 side (lower side) of the cylinder block 3. The engine main body 2 includes a timing chain cover 6 attached to a side end portion of the cylinder block 3 and a head cover 7 attached to the cylinder head 4.

In the cylinder head 4, as illustrated in FIG. 2, an intake valve 4 b that is periodically opened and closed by rotation of an intake cam shaft 4 a, an exhaust valve 4 d that is periodically opened and closed by rotation of an exhaust cam shaft 4 c, and an ignition plug (not illustrated) are incorporated. In addition, the cylinder head 4 also includes a combustion chamber 4 f, an intake port 4 g for feeding suction air to the combustion chamber 4 f, and an exhaust port 4 h for discharging burned gas. The intake port 4 g is connected to an intake manifold (not illustrated). The exhaust port 4 h is connected to an exhaust manifold (not illustrated).

The combustion chamber 4 f is formed in the upper portion in the cylinder 3 a, and is configured to combust the air taken in from the intake port 4 g and fuel by the ignition plug. Inside each of the plurality of cylinders 3 a, the piston 8 accommodated to be capable of reciprocating, and a connecting rod 9 for connecting the piston 8 and the crankshaft 10 to each other are provided.

Further, an intake variable valve timing mechanism (not illustrated, and hereinafter, referred to as an intake VVT) that shifts rotation in a retarding direction or in an advancing direction is attached to the intake cam shaft 4 a. In addition, an exhaust variable valve timing mechanism (not illustrated, and hereinafter, referred to as an exhaust VVT) that shifts rotation in a retarding direction or in an advancing direction is attached to the exhaust cam shaft 4 c.

As illustrated in FIG. 1, the engine main body 2 includes an oil supply device 20 that circulates an oil A (engine oil) inside and supplies the oil A to each portion of the engine 1. The oil supply device 20 includes an oil pan 21 that stores the oil A circulating in the engine 1, and an oil pump 22 (O/P) for suctioning up the oil A in the oil pan 21 and supplying the oil A in the oil pan 21 to each portion of the engine 1. The oil pump 22 is rotated using a driving force of the crankshaft 10. As illustrated in FIG. 3, the oil pump 22 discharges the oil A from a discharge port 51 b in a state (compressed state) where a pump chamber 54 is reduced and a predetermined oil pressure is generated after suctioning the oil A from the oil pan 21 (refer to FIG. 2) to the pump chamber 54 via a suction port 51 a. In addition, the detailed configuration of the oil pump 22 will be described later.

As illustrated in FIG. 1, the oil supply device 20 includes an oil supply flow passage 23 for flowing the oil A discharged from the oil pump 22. The oil supply flow passage 23 includes a lubrication flow passage 31 for supplying the oil A to a lubrication portion 24 of the engine 1 and a cooling flow passage 32 provided being branched from the lubrication flow passage 31 for supplying the oil A to the cooling object 25. Here, the lubrication portion 24 is a member, such as a bearing 5 a of the crankshaft 10, an intake cam shaft 4 a, an exhaust cam shaft 4 c, the intake VVT, the exhaust VVT, or the like, for supplying the oil A that circulates in the engine 1 in order to reduce the friction between the configurations in the engine 1. The cooling object 25 is a member, such as the cylinder 3 a (a member located at the outer periphery of the piston 8), the cylinder head 4, and the piston 8 which are cooled by supplying the oil A that circulates in the engine 1.

The lubrication flow passage 31 includes a first oil passage 31 a that connects the oil pan 21 and the suction port 51 a of the oil pump 22, a second oil passage 31 b that connects the discharge port 51 b of the oil pump 22 and a main oil gallery 31 c to each other, a main oil gallery 31 c, and a third oil passage 31 d that extends upward (Z1 side) from the end portion (X2 side end portion) on the downstream side of the main oil gallery 31 c. In addition, the lubrication flow passage 31 includes an oil supply pipe 31 e connected to the downstream side of the third oil passage 31 d. By supplying the oil A to the intake cam shaft 4 a and the exhaust cam shaft 4 c, a cam shower 26 for lubricating the intake cam shaft 4 a and the exhaust cam shaft 4 c is attached to the oil supply pipe 31 e. In addition, the lubrication flow passage 31 includes a bearing oil passage 31 f that is branched from the main oil gallery 31 c and supplies the oil A to the bearing 5 a of the crankshaft 10.

The cooling flow passage 32 includes a piston cooling oil passage 32 a (one example of “combustion chamber cooling flow passage” in the appended claims) that is branched from the main oil gallery 31 c and supplies the oil A to the piston 8. An oil jet mechanism 27 is provided in the end portion on the downstream side of the piston cooling oil passage 32 a. The oil jet mechanism 27 has a function of lubricating a part around the piston 8 while cooling the piston 8 by injecting the cooling oil A to the rear side of the piston 8 by opening a valve at a predetermined operating pressure.

The cooling flow passage 32 includes a cylinder head cooling oil passage 32 b (one example of “combustion chamber cooling flow passage” in the appended claims) that is branched from the oil supply pipe 31 e and supplies the oil A to the cylinder head 4. An injection nozzle 28 is provided in the end portion on the downstream side of the cylinder head cooling oil passage 32 b. The injection nozzle 28 has a function of cooling the combustion chamber 4 f (refer to FIG. 2) by cooling the cylinder head 4 by injecting the cooling oil A to an inner surface portion 4 e of the cylinder head 4.

The cooling flow passage 32 includes a cylinder cooling oil passage 32 c (one example of “combustion chamber cooling flow passage” in the appended claims) that is branched from the main oil gallery 31 c and supplies the oil A to the cylinder 3 a. An injection nozzle 29 is provided in the end portion on the downstream side of the cylinder cooling oil passage 32 c. The injection nozzle 29 has a function of cooling the combustion chamber 4 f (refer to FIG. 2) by cooling the cylinder 3 a by injecting the cooling oil A to the inner surface of the cylinder 3 a.

In this manner, in the oil supply device 20, the plurality of cooling flow passages 32, such as the piston cooling oil passage 32 a, the cylinder head cooling oil passage 32 b, and the cylinder cooling oil passage 32 c, are provided being branched from the lubrication flow passage 31.

The oil supply device 20 includes a reflux passage 30 for returning the oil A supplied to the intake cam shaft 4 a and the exhaust cam shaft 4 c and the oil A supplied to the inner surface portion 4 e of the cylinder head 4, to the oil pan 21. Here, in the oil supply device 20, the oil A supplied to the bearing 5 a of the crankshaft 10 and the oil A supplied to the piston 8 fall by the own weight without passing through the reflux passage 30, and are returned to the oil pan 21.

Air Mixing Portion

In the oil supply device 20 of the embodiment, as illustrated in FIG. 2, the oil jet mechanism 27 and the injection nozzle 28 are respectively configured as an air mixing portion 40. In other words, the air mixing portion 40 is disposed in the end portion on the downstream side of the cooling flow passage 32 (the piston cooling oil passage 32 a, the cylinder head cooling oil passage 32 b, and the cylinder cooling oil passage 32 c). In addition, the air mixing portion 40 is configured to mix an air B into the oil A supplied to the oil supply flow passage 23 and cool the cooling object 25 (the piston 8, the cylinder head 4, and the cylinder 3 a) by supplying the oil A mixed with the air B to the cooling object 25. In other words, the air mixing portion 40 is configured to cause the air B to be caught in the oil A supplied to the cooling object 25 and supply the oil A mixed with the air B to the cooling object 25. Here, the air mixing portion 40 deposits the oil A on the cooling object 25 by injecting the oil A.

Specifically, as illustrated in FIG. 4, the air mixing portion 40 includes a turbulence generation portion 41 that generates a turbulence in the flow of the oil A that flows inside, as a mechanism for causing the air B to be caught into the oil A. The turbulence generation portion 41 is configured to generate the turbulence in the flow of the oil A, and cause the air B to be caught at a part around the oil A of the turbulence discharged from the discharge port 45 in the oil A by the turbulence inside the oil A. The turbulence generation portion 41 includes a reduced diameter portion 42 in which a flow passage diameter of the section orthogonal to an oil discharge direction D on the upstream side is smaller than a flow passage diameter of the section orthogonal to the oil discharge direction D. As the reduced diameter portion 42 goes to the downstream side in the oil discharge direction D, the reduced diameter portion 42 gradually narrows on the center portion side of the flow passage.

Accordingly, the flow of the oil A at the outer part of the oil A that has flowed to the reduced diameter portion 42 is the flow of the oil A in a direction different from the flow of the oil A on the upstream side of the reduced diameter portion 42 by abutting against an inner wall portion 44 of the reduced diameter portion 42. As a result, in the reduced diameter portion 42, due to a change in flow of the oil A at the outer part, the flow of the oil A at another part also changes, and thus, the turbulence is generated. In other words, the flow passage in the reduced diameter portion 42 is a turbulence generation region that disturbs the flow of the oil A. In addition, the flow velocity of the oil A that flows through the reduced diameter portion 42 becomes faster than the flow velocity of the oil A on the upstream side of the reduced diameter portion 42 as the flow passage diameter of the section orthogonal to the oil discharge direction D decreases. Accordingly, in the air mixing portion 40, the turbulence is more likely to be generated in the reduced diameter portion 42.

As illustrated in FIG. 5, the reduced diameter portion 42 is a polygonal shape (pentagonal shape) having a rounded circular arc side portion 43 when viewed from the oil discharge direction D. Here, the flow passage in the reduced diameter portion 42 is a polygonal shape (pentagonal shape) having the rounded circular arc side portion 43 when viewed from the oil discharge direction D. In other words, the inner wall portion 44 in the reduced diameter portion 42 includes a plurality of arc portions 44 a. Accordingly, a surface area of the inner wall portion 44 in the reduced diameter portion 42 is larger than the surface area of the inner wall portion 44 in a case where the flow passage in the reduced diameter portion 42 is circular. As a result, since the shape viewed from the oil discharge direction D of the oil A discharged from the discharge port 45 of the reduced diameter portion 42 also becomes a pentagonal shape having the rounded circular arc side portions 43, it is possible to increase the amount of the air B that is in contact with the oil A discharged from the discharge port 45 of the reduced diameter portion 42 compared to a case where the flow passage in the reduced diameter portion 42 has a circular shape.

In this manner, as illustrated in FIG. 4, the air mixing portion 40 is configured to cause the air B in an air mixing region in the vicinity of the discharge port 45 to be caught in the oil A in which the turbulence is generated, and to take the air B into the oil A as air bubbles.

Cooling by Oil Mixed with Air

With reference to FIGS. 6 to 9, a cooling capability of the oil A mixed with the air B when the oil A mixed with the air B by the air mixing portion 40 is supplied to the surface of the cooling object 25 will be described. Here, the cooling capability with respect to the cooling object 25 changes depending on the heat transfer coefficient of the oil A mixed with the air B and the size of the cooling area. In other words, the larger the heat transfer coefficient and the cooling area, the more heat amount can be removed from the cooling object 25.

As illustrated in FIGS. 6 and 7, the oil A mixed with the air B injected from the air mixing portion 40 is supplied to the surface of the cooling object 25 and spreads over the surface of the cooling object 25. Here, when comparing each case where the oil A mixed with the air B illustrated in FIG. 8A and the oil A that is not mixed with the air B illustrated in FIG. 8B are respectively injected onto the surface of the cooling object 25 with the same amount, the oil A mixed with the air B spreads over a wider range.

The reason why the oil A mixed with the air B spreads over a wider range is considered, for example, as follows. In the oil A mixed with air B, a contact area between the surface of the cooling object 25 and the oil A is smaller than that in a case where only the oil A (the oil A that is not mixed with the air B) is used as much as the air B is mixed thereinto. Accordingly, since a frictional force generated between the oil A mixed with the air B and the surface of the cooling object 25 is smaller than that in a case where only the oil A is used, the oil A mixed with the air B spreads over a wider range.

With reference to FIG. 9, a relationship between the flow velocity and the heat transfer coefficient for the injection to the surface of the cooling object 25 in three types of fluids including the water, the oil A mixed with the air B, and the oil A (the oil A that is not mixed with the air B) will be described. When comparing the water, the oil A mixed with the air B, and the oil A with each other, it is understood that the heat transfer coefficient decreases in the order of the water A, the oil A mixed with the air B, and the oil A.

Air Separating Portion

As illustrated in FIG. 2, the oil pump 22 is configured as an air separating portion 50 that separates the air B from the oil A containing the air B that has returned to the oil pan 21 after being supplied to the cooling object 25. In other words, the oil pump 22 is configured to separate the air B from the oil A containing the air B that has returned to the oil pan 21 after being supplied to the cooling object 25 by the air mixing portion 40, and supply the oil A separated from the air B to the oil supply flow passage 23.

In other words, specifically, as illustrated in FIG. 3, the oil pump 22 includes a housing 51, an inner rotor 52, and an outer rotor 53. The inner rotor 52 has external teeth 52 a and a discharge groove 52 c formed in an upper valley part 52 b between the external teeth 52 a. The outer rotor 53 has internal teeth 53 a engaged with the external teeth 52 a of the inner rotor 52. A pump chamber 54 is formed between the external teeth 52 a of the inner rotor 52 and the internal teeth 53 a of the outer rotor 53. In the housing 51, the suction port 51 a for guiding the oil A into the pump chamber 54 between the external teeth 52 a and the internal teeth 53 a is formed. Further, in the housing 51, the discharge port 51 b for guiding the oil A to the outside of the pump chamber 54 is formed. In addition, in the housing 51, discharge holes 51 c are formed so as to communicate with the discharge grooves 52 c and guide the air bubbles contained in the oil A to the outside of the pump chamber 54.

In the oil pump 22, the pump chamber 54 is expanded and reduced together with the rotational movement in an arrow R direction to create a pump function. The suction port 51 a is connected to the oil pan 21, and the oil A is supplied from the oil pan 21. The discharge port 51 b is connected to the oil supply flow passage 23.

Here, the discharge hole 51 c communicates earlier than the timing at which the pump chamber 54 and the discharge port 51 b communicate with each other and later than the timing at which a volume of the pump chamber 54 is maximized. In other words, in the oil pump 22, since the pump chamber 54 and the discharge hole 51 c communicate with each other at the timing when the volume of the pump chamber 54 starts to be reduced, it is possible to discharge the oil A mixed with the separated air B to the oil pan 21 via the discharge groove 52 c from the discharge hole 51 c as illustrated in FIG. 2.

Effects of Embodiment

In the embodiment, the following effects can be obtained.

In the embodiment, as described above, the oil supply device 20 includes the air mixing portion 40 for cooling the cooling object 25 by mixing the air B into the oil A supplied to the oil supply flow passage 23 and supplying the oil A mixed with the air B to the cooling object 25. Accordingly, since the friction with the cooling object 25 decreases by mixing the air B into the oil A compared to a case of supplying the oil A that is not mixed with the air B to the cooling object 25, the oil A can be spread over a wide range on the surface of the cooling object 25. In addition, since the oil A can be spread over a wide range on the surface of the cooling object 25, the contact area between the oil A and the cooling object 25 can be increased, and it is possible to improve the heat transfer coefficient with the cooling object 25. At this time, since it is possible to remove the heat from the wide range of the cooling object 25 by the oil A on the surface of the cooling object 25, it is possible to efficiently move the heat to the layer of the oil A from the cooling object 25. Therefore, compared to a case of supplying the oil A that is not mixed with the air B to the cooling object 25, it is possible to efficiently remove the heat from the cooling object 25 by the oil A mixed with the air B, and thus, it is possible to reduce the amount of the oil A required to cool the cooling object 25. As a result, since it is possible to suppress the amount of the oil A held in the device, it is possible to suppress the increase in size of the oil supply device 20.

In addition, compared to a case of supplying the oil A that is not mixed with the air B to the cooling object 25, by efficiently removing the heat from the cooling object 25 from the oil A mixed with the air B, it is possible to cool the cooling object 25 by the oil A supplied from the oil supply device 20 instead of cooling the cooling object 25 by a coolant, and thus, it is possible to reduce or eliminate the coolant, a cooling pump, piping, and the like. As a result, it is possible to achieve simplification, reduction in size, and reduction in weight of the configuration of the engine 1, and it is possible to reduce energy consumption.

In addition, in the embodiment, as described above, the oil supply flow passage 23 includes the lubrication flow passage 31 for supplying the oil A to the lubrication portion 24, and the cooling flow passage 32 provided being branched from the lubrication flow passage 31 for supplying the oil A to the cooling object 25, and the air mixing portion 40 is disposed in the cooling flow passage 32. Accordingly, since it is possible to simplify the configuration of the flow passage in the device compared to a case where the flow passage for supplying the oil A to the lubrication portion 24 and the flow passage for supplying the oil A mixed with the air B to the cooling object 25 are separately provided, it is possible to further suppress the increase in size of the oil supply device 20. In addition, since it is possible to supply the oil A mixed with the air B for cooling the cooling object 25 and to supply the oil A for lubrication of the lubrication portion 24 by one oil pump 22, it is possible to further suppress the increase in size of the oil supply device 20.

In addition, in the embodiment, as described above, the air mixing portion 40 is disposed in the end portion on the downstream side of the cooling flow passage 32. Accordingly, it is possible to suppress that the cooling oil A mixed with the air B supplied by the air mixing portion 40 flows into the lubrication flow passage 31. In addition, simply by changing a nozzle in the end portion on the downstream side of the cooling flow passage 32 in the existing oil supply device, it is possible to improve the cooling effect without making a substantial change in the device.

In addition, in the embodiment, as described above, the oil supply device 20 includes: the oil pan 21 for storing the oil A; and the air separating portion 50 for separating the air B from the oil A containing the air B that has returned to the oil pan 21 after being supplied to the cooling object 25. Accordingly, by separating the air B by the air separating portion 50 from the oil A mixed with the air B that has been supplied to the cooling object 25 and has returned to the oil pan 21, it is possible to suppress the flow of the oil A mixed with the air B to the lubrication flow passage 31.

In addition, in the embodiment, as described above, the cooling flow passage 32 includes the cylinder head cooling oil passage 32 b, the piston cooling oil passage 32 a, and the cylinder cooling oil passage 32 c through which the oil A for cooling each of the cylinder head 4, the piston 8, and the cylinder 3 a of the engine 1 that serves as the cooling object 25 flows. The air mixing portion 40 is disposed in each of the cylinder head cooling oil passage 32 b, the piston cooling oil passage 32 a, and the cylinder cooling oil passage 32 c. Accordingly, since it is possible to efficiently cool the configuration component of the engine that is likely to have high temperature due to the combustion heat, it is possible to suppress the occurrence of overheat.

Modification Example

It should be understood that the embodiment disclosed here is an example and is non-restrictive in every respect. The scope of the disclosure is indicated not by the description of the embodiment but by the scope of the appended claims, and further includes all modifications (modification examples) within the scope and meaning equivalent to the scope of the appended claims.

For example, in the embodiment, an example in which the oil pump 22 discharges the oil A mixed with the separated air bubbles from the discharge hole 51 c to the oil pan 21 via the discharge groove 52 c, is illustrated, but the disclosure is not limited thereto. In the disclosure, as illustrated in a first modification example in FIG. 10, an oil pump 122 may be configured to use the oil A mixed with the separated air B for cooling the cooling object 25 by supplying the oil A to an air mixing portion 140, when the air B is separated from the oil A containing the air B.

In addition, in the embodiment, an example in which the air mixing portion 40 is configured to supply the oil A mixed with the air B to the cooling object 25 by causing the air B to be caught in the oil A supplied to the cooling object 25 is illustrated, but the disclosure is not limited thereto. In the disclosure, an air mixing portion 240 may have a venturi shape as illustrated in a second modification example in FIG. 11. In other words, the air mixing portion 240 includes an inflow portion 261 into which the oil flows, and an outflow portion 262 in which the oil that flows in from the inflow portion 261 flows out. In addition, the air mixing portion 240 includes a reduction portion 263 that is provided between the inflow portion 261 and the outflow portion 262 and has a flow passage sectional area smaller than the flow passage sectional area of both the inflow portion 261 and the outflow portion 262, and an air supply portion 264 that is connected to the reduction portion 263 and supplies the air to the oil. In addition, the flow passage sectional area of the air supply portion 264 is smaller than the flow passage sectional area of the reduction portion 263.

In addition, in the second modification example, an example in which the air mixing portion 240 is configured to supply the ambient air B to the oil A in the reduction portion 263 is illustrated, but the disclosure is not limited thereto. In the disclosure, the air mixing portion may be configured to supply fresh air to the oil in the reduction portion.

In addition, in the first modification example, an example in which the oil pump 122 is configured to use the oil A mixed with the separated air B for cooling the cooling object 25 by supplying the oil A to the air mixing portion 40, when the air B is separated from the oil A containing the air B is illustrated, but the disclosure is not limited thereto. In the disclosure, as illustrated in a third modification example in FIG. 12, an oil pump 322 may be configured to use the oil A mixed with the separated air B for cooling another cooling object 25 different from the cooling object 25 that supplies the oil A containing the air B by the air mixing portion 140, when the air B is separated from the oil A containing the air B. Here, the oil A containing the air B is supplied to the cylinder head 4 by the air mixing portion 40, and the oil A mixed with the air B separated by the oil pump 322 is supplied to the piston 8 and a cylinder 8 a.

In addition, in the first modification example, an example in which the oil pump 122 is configured to use the oil A mixed with the separated air B for cooling the cooling object 25 by supplying the oil A to the air mixing portion 140, when the air B is separated from the oil A containing the air B is illustrated, but the disclosure is not limited thereto. In the disclosure, as illustrated in a fourth modification example in FIG. 13, an oil pump 422 may be configured to use the oil A mixed with the separated air B for cooling and lubrication by supplying the oil A to a non-high-accuracy lubrication portion 424 a (the intake cam shaft 4 a or the exhaust cam shaft 4 c) that can perform lubrication by the oil A containing the air B, when the air B is separated from the oil A containing the air B.

In addition, in the first modification example, an example in which the air mixing portion 140 is disposed on the downstream side of each of the plurality of cooling flow passages 32 is illustrated, but the disclosure is not limited thereto. In the disclosure, as illustrated in fifth modification example in FIG. 14, an air mixing portion 540 may be disposed on the downstream side of a branch position D1 from the lubrication flow passage 31 and on the upstream side of a branch positions D2 of the plurality of cooling flow passages 32. In other words, the oil supply flow passage 23 includes a first branch position D1 and a second branch position D2, the first branch position branches D1 the lubrication flow passage 31 and the cooling flow passage 32, the second branch position branches D2 the single cooling flow passage 32 to the plurality of cooling flow passage 32(32 a, 32 b, 32 c, 31 e), the air mixing portion 540 may be disposed between the first branch portion D1 and a second branch position D2. Here, the oil supply pipe 31 e is the cooling flow passage 32. Accordingly, by disposing the air mixing portion 540 on the common oil supply flow passage 23 positioned on the upstream side of the plurality of cooling flow passages 32, it is not necessary to provide the air mixing portion 540 individually for each of the plurality of cooling flow passages 32, and thus, it is possible to simplify the configuration, and to further suppress the increase in size of the oil supply device 520.

In addition, in the embodiment, an example in which the oil supply device 20 includes the cylinder head 4, the cylinder 3 a, and the piston 8 as the cooling object 25 and the bearing 5 a or the like as the lubrication portion 24 is illustrated, but the disclosure is limited thereto. In the disclosure, as illustrated in a sixth modification example in FIG. 15, an oil supply device 620 may include a vehicle driving motor 671 that serves as the cooling object to which the oil containing the air of the cooling flow passage is supplied, and a speed changer mechanism portion 610 (one example of a transmission mechanism portion) to which the oil of the lubrication flow passage is supplied and that serves as the lubrication portion for transmitting the driving force of the vehicle driving motor 671 to wheels. Here, in the oil supply device 620, in order to supply the oil containing the air to the vehicle driving motor 671, an air mixing portion 640 is disposed on the upstream side of the vehicle driving motor 671 of an oil supply flow passage 623 connected to an oil pump 622. In addition, the oil mixed with the air is supplied to a heating element (for example, coil) on the inside of the vehicle driving motor 671.

In addition, in the embodiment, an example in which the reduced diameter portion 42 has a pentagonal shape having the rounded circular arc side portions 43 when viewed from the oil discharge direction D is illustrated, but the disclosure is not limited thereto. In the disclosure, the reduced diameter portion may have a polygonal shape other than a pentagonal shape having rounded circular arc side portions.

In addition, in the embodiment, an example in which the turbulence generation portion 41 includes a reduced diameter portion 42 in which a flow passage diameter of the section orthogonal to the oil discharge direction D is smaller than a flow passage diameter of the section orthogonal to the oil discharge direction D on the upstream side, is illustrated, but the disclosure is not limited thereto. In the disclosure, the turbulence generation portion may be configured with the plurality of protruding walls formed on the inner wall of the cooling flow passage to prevent the flow of the oil.

In addition, in the embodiment, an example in which the oil pump 22 is configured as the air separating portion 50 is illustrated, but the disclosure is not limited thereto. In the disclosure, in the air separating portion, not the oil pump, but a gas-liquid separation chamber that separates the air from the oil mixed with the air may be disposed on the upstream side of the oil pump.

In addition, in the embodiment, an example in which the oil supply device 20 is applied to the engine 1 for vehicles and cools the cooling object 25 is illustrated, but the disclosure is not limited thereto. In the disclosure, the oil supply device may be configured to cool the cooling object provided in the engine or the like of a gas cogeneration system.

In addition, in the embodiment, an example in which the cylinder 3 a is cooled by the cylinder cooling oil passage 32 c provided with the injection nozzle 29 is illustrated, but the disclosure is not limited thereto. In the disclosure, the cylinder cooling oil passage may be configured to dispose the reflux passage around the cylinder and cool the cylinder while returning the oil to the oil pan.

An oil supply device according to an aspect of this disclosure includes: an oil pump; an oil supply flow passage through which oil discharged from the oil pump flows; and an air mixing portion that cools a cooling object by mixing air into the oil supplied to the oil supply flow passage and supplying the oil mixed with the air to the cooling object.

The oil supply device according to the aspect of the disclosure includes the air mixing portion for cooling the cooling object by mixing the air into the oil supplied to the oil supply flow passage and supplying the oil mixed with the air to the cooling object. Accordingly, since friction with the cooling object decreases by mixing the air into the oil compared to a case of supplying the oil that is not mixed with the air to the cooling object, the oil can be spread over a wide range on the surface of the cooling object. In addition, since the oil can be spread over a wide range on the surface of the cooling object, the contact area between the oil and the cooling object can be increased, and a thin oil layer can be formed on the surface of the cooling object. At this time, the oil on the surface of the cooling object can remove heat from the wide range of the cooling object, the oil layer is likely to be cooled by a heat transfer promoting effect by the air mixing, and thus, it is possible to efficiently move the heat from the cooling object to the oil layer. Therefore, compared to a case of supplying the oil that is not mixed with the air to the cooling object, it is possible to efficiently remove the heat from the cooling object by the oil mixed with the air, and thus, it is possible to reduce the amount of oil required to cool the cooling object. As a result, since it is possible to suppress the amount of oil held in the device, it is possible to suppress the increase in size of the oil supply device.

In the oil supply device according to the aspect, it is preferable that the oil supply flow passage includes a lubrication flow passage that supplies the oil to a lubrication portion, and a cooling flow passage that is provided to be branched from the lubrication flow passage and supplies the oil to the cooling object, and the air mixing portion is disposed in the cooling flow passage.

With this configuration, since it is possible to simplify the configuration of the flow passage in the device compared to a case where the flow passage for supplying the oil to the lubrication portion and the flow passage for supplying the oil mixed with the air to the cooling object are separately provided, it is possible to further suppress the increase in size of the oil supply device. In addition, since it is possible to supply the oil mixed with the air for cooling the cooling object and to supply the oil for the lubrication of the lubrication portion by one oil pump, it is possible to further suppress the increase in size of the oil supply device.

In the oil supply device in which the cooling flow passage is provided to be branched from the lubrication flow passage, it is preferable that the air mixing portion is disposed in an end portion on a downstream side of the cooling flow passage.

With this configuration, it is possible to suppress that the cooling oil mixed with the air supplied by the air mixing portion flows into the lubrication flow passage. In addition, simply by changing a nozzle in the end portion on the downstream side of the cooling flow passage to the air mixing portion in the existing oil supply device, it is possible to improve the cooling effect without making a substantial change in the device.

In the oil supply device in which the cooling flow passage is provided to be branched from the lubrication flow passage, it is preferable that a plurality of the cooling flow passages are provided to be branched from the lubrication flow passage, and the air mixing portion is disposed on the downstream side of a branch position from the lubrication flow passage and on an upstream side of a branch position of the plurality of cooling flow passages.

With this configuration, by disposing the air mixing portion on a common oil supply flow passage disposed on the upstream side of the plurality of cooling flow passages, it is not necessary to provide the air mixing portion individually for each of the plurality of cooling flow passages, and thus, it is possible to simplify the configuration, and to further suppress the increase in size of the oil supply device.

It is preferable that the oil supply device according to the aspect further includes an oil pan that stores the oil; and an air separating portion that separates the air from the oil containing the air that has returned to the oil pan after being supplied to the cooling object.

With this configuration, by separating the air by the air separating portion from the oil mixed with the air that has been supplied to the cooling object and has returned to the oil pan, it is possible to suppress the flow of the oil mixed with the air to the lubrication flow passage.

In the oil supply device in which the cooling flow passage is branched from the lubrication flow passage, it is preferable that the cooling flow passage includes a combustion chamber cooling flow passage through which the oil for cooling at least one of a cylinder head, a cylinder, and a piston of an engine that serves as at least the cooling object flows, and the air mixing portion is disposed in the combustion chamber cooling flow passage.

With this configuration, since it is possible to efficiently cool the configuration component of the engine that is likely to have high temperature due to the combustion heat, it is possible to suppress the occurrence of overheat.

In addition, according to this disclosure, the following configurations are also conceivable for the oil supply device according to the aspect.

In the oil supply device provided with the air separating portion, it is preferable that the air separating portion is configured with the oil pump, and the oil pump separates the air from the oil containing the air that has returned to the oil pan after being supplied to the cooling object by the air mixing portion, and supplies the oil from which the air is separated.

With this configuration, since the oil pump is used as the air separating portion, it is possible to reduce the number of components of the device compared to a case where the air separating portion is provided separately from the oil pump. Accordingly, it is possible to simplify the configuration of the oil supply device, and to further suppress the increase in size.

In the oil supply device in which the air separating portion is configured with the oil pump, it is preferable that the oil pump includes an inner rotor having external teeth, an outer rotor having internal teeth engaged with the external teeth, a housing that accommodates the inner rotor and the outer rotor, and a pump chamber formed in the housing, and the air separating portion is a discharge hole for discharging the air contained in the oil from the pump chamber.

With this configuration, since it is possible to discharge the air contained in the oil from the pump chamber simply by forming the discharge hole in the housing of the oil pump, it is possible to easily form the air separating portion.

In the oil supply device in which the air separating portion is configured with the oil pump, it is preferable that the oil pump supplies the oil mixed with the separated air to the air mixing portion when the air is separated from the oil containing the air.

With this configuration, by reusing the oil mixed with the air separated by the air separating portion, it is possible to sufficiently ensure the amount of oil mixed with the air supplied from the air mixing portion to the cooling object, and thus, it is possible to sufficiently cool the cooling object.

In the oil supply device according to the aspect, it is preferable that the air mixing portion includes an inflow portion into which the oil flows, and an outflow portion from which the oil that has flowed in from the inflow portion flows out, a reduction portion that is provided between the inflow portion and the outflow portion and has a flow passage sectional area smaller than the flow passage sectional areas of both the inflow portion and the outflow portion, and an air supply portion that is connected to the reduction portion and supplies the air to the oil.

With this configuration, since it is possible to increase a flow velocity of the oil that flows through the reduction portion to generate a negative pressure, it is possible to effectively draw the air into the oil. As a result, since it is possible to reliably mix the air into the oil, it is possible to stabilize the cooling performance for the cooling object.

In the oil supply device according to the aspect, it is preferable that the air mixing portion includes a turbulence generation portion that generates a turbulence in the flow of the oil, and the air mixing portion generates a turbulence in the flow of the oil by the turbulence generation portion and causes the air around the oil of the turbulence flowed out from a discharge port to be caught in the oil by the turbulence inside the oil.

With this configuration, since it is possible to mix a larger amount of air around the oil with the oil when the oil flows out from discharge port compared to a case where the flow in the oil that flows out from the discharge port is not a turbulence, it is possible to efficiently cool the cooling object.

In the oil supply device including the air supply portion including the reduction portion, it is preferable that the air supply portion supplies fresh air to the reduction portion.

With this configuration, since it is possible to supply the oil mixed with the fresh air having a relatively low temperature to the cooling object, compared to a case where the air having a relatively high temperature in the vicinity of the air mixing portion is mixed into the oil, it is possible to improve cooling performance with respect to the cooling object.

In the oil supply device in which the air separating portion is configured with the oil pump, it is preferable that the oil pump supplies the oil mixed with the separated air to a cooling object that is different from the cooling object to which the oil containing the air is supplied by the air mixing portion, when the air is separated from the oil containing the air.

With this configuration, since the oil mixed with the air separated in the oil pump is supplied to another cooling object without providing the cooling flow passage in which the air mixing portion is disposed, it is possible to effectively utilize the oil mixed with the air separated in the oil pump.

In the oil supply device in which the air separating portion is configured with the oil pump, it is preferable that the lubrication portion includes a non-high-accuracy lubrication portion capable of being lubricated by the oil containing the air, and the oil pump supplies the oil mixed with the separated air to the non-high-accuracy lubrication portion when the air is separated from the oil containing the air.

With the configuration, for example, since the oil mixed with the air is supplied to the non-high-accuracy lubrication portion that does not require high-accuracy lubrication, such as a cam shaft, it is possible to effectively utilize the oil mixed with the separated air generated in the oil pump. In addition, in a case of the non-high-accuracy lubrication portion that does not require high-accuracy lubrication, such as the cam shaft, even when the oil mixed with the air is supplied, there is no hindrance to the lubrication.

It is preferable that the oil supply device including the oil supply flow passage including the cooling flow passage, further includes a vehicle driving motor to which the oil containing the air of the cooling flow passage is supplied, and a transmission mechanism portion to which the oil of the lubrication flow passage is supplied and which transmits a driving force of the vehicle driving motor to wheels.

With this configuration, it is possible to effectively cool the vehicle driving motor compared to a case where the oil that is not mixed with the air is supplied and to lubricate the transmission mechanism portion.

The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby. 

What is claimed is:
 1. An oil supply device comprising: an oil pump; an oil supply flow passage through which oil discharged from the oil pump flows; and an air mixing portion that cools a cooling object by mixing air into the oil supplied to the oil supply flow passage and supplying the oil mixed with the air to the cooling object.
 2. The oil supply device according to claim 1, wherein the oil supply flow passage includes a lubrication flow passage that supplies the oil to a lubrication portion, and a cooling flow passage that is provided to be branched from the lubrication flow passage and supplies the oil to the cooling object, and the air mixing portion is disposed in the cooling flow passage.
 3. The oil supply device according to claim 2, wherein the air mixing portion is disposed in an end portion on a downstream side of the cooling flow passage.
 4. The oil supply device according to claim 2, wherein a plurality of the cooling flow passages are provided to be branched from the lubrication flow passage, and the air mixing portion is disposed on the downstream side of a branch position from the lubrication flow passage and on an upstream side of a branch position of the plurality of cooling flow passages.
 5. The oil supply device according to claim 2, wherein the oil supply flow passage includes a first branch position and a second branch position, the first branch position branches the lubrication flow passage and the cooling flow passage, the second branch position branches the single cooling flow passage to the plurality of cooling flow passage, and the air mixing portion is disposed downstream of the first branch position and upstream of the second branch position.
 6. The oil supply device according to claim 1, further comprising: an oil pan that stores the oil; and an air separating portion that separates the air from the oil containing the air that has returned to the oil pan after being supplied to the cooling object.
 7. The oil supply device according to claim 2, wherein the cooling flow passage includes a combustion chamber cooling flow passage through which the oil for cooling at least one of a cylinder head, a cylinder, and a piston of an engine that serves as at least the cooling object flows, and the air mixing portion is disposed in the combustion chamber cooling flow passage.
 8. The oil supply device according to claim 6, wherein the air separating portion is configured with the oil pump, and the oil pump separates the air from the oil containing the air that has returned to the oil pan after being supplied to the cooling object by the air mixing portion, and supplies the oil from which the air is separated.
 9. The oil supply device according to claim 8, wherein the oil pump includes an inner rotor having external teeth, an outer rotor having internal teeth engaged with the external teeth, a housing that accommodates the inner rotor and the outer rotor, and a pump chamber formed in the housing, and the air separating portion is a discharge hole for discharging the air contained in the oil from the pump chamber.
 10. The oil supply device according to claim 8, wherein the oil pump supplies the oil mixed with the separated air to the air mixing portion when the air is separated from the oil containing the air.
 11. The oil supply device according to claim 1, wherein the air mixing portion includes an inflow portion into which the oil flows in, and an outflow portion from which the oil that has flowed in from the inflow portion flows out, a reduction portion that is provided between the inflow portion and the outflow portion and has a flow passage sectional area smaller than the flow passage sectional areas of both the inflow portion and the outflow portion, and an air supply portion that is connected to the reduction portion and supplies the air to the oil.
 12. The oil supply device according to claim 11, wherein the air mixing portion includes a turbulence generation portion that generates a turbulence in the flow of the oil, and the air mixing portion generates a turbulence in the flow of the oil by the turbulence generation portion and causes the air around the oil of the turbulence flowed out from a discharge port to be caught in the oil by the turbulence inside the oil.
 13. The oil supply device according to claim 11, wherein the air supply portion supplies fresh air to the reduction portion.
 14. The oil supply device according to claim 1, wherein the oil pump supplies the oil mixed with the separated air to a cooling object that is different from the cooling object to which the oil containing the air is supplied by the air mixing portion, when the air is separated from the oil containing the air.
 15. The oil supply device according to claim 2, wherein the lubrication portion includes a non-high-accuracy lubrication portion capable of being lubricated by the oil containing the air, and the oil pump supplies the oil mixed with the separated air to the non-high-accuracy lubrication portion when the air is separated from the oil containing the air.
 16. The oil supply device according to claim 2, further comprising: a vehicle driving motor to which the oil containing the air of the cooling flow passage is supplied, and a transmission mechanism portion to which the oil of the lubrication flow passage is supplied and which transmits a driving force of the vehicle driving motor to wheels. 